Strange z-axis movement on Rostock

Hey,

I just built my first Rostock printer, and I'm having some problems. The printer homes fine, there is nothing wrong with that, but every time I try to move it in the z axis, it does move down, but it also moves to one tower. I don't think that it is a hardware problem, because if I swap all of the motor cables around to other headers, the print head moves to other sides of the build plate. I've looked around for a possible cause online, but I haven't found anything yet. Here is my Configuration.h file. It would be really awesome if someone could help me out. Thanks.

Hi, I too just built a rostock and I just got it working. I'm more familiar with marlin firmware vs repetier firmware, but I gave your config. H file a look and I have a few questions as to whether your Rostock was built to Johanns original specs or if you modified it?

The reason that I ask is because your mechanical dimensions in the attached file are much smaller than a rostock-- delta diagnonal rod is: 195 vs 250, center smooth rod is: 139.5 vs 175, etc. if those are your correct dimensions that were measured then that's okay, but if this was the original rostock then I would adjust the firmware to the correct measurements and see if some of the problems go away.

For a delta on the z axis, all 3 motors need to movie together in sync. If the carriage is moving in a direction on the x or y axis when it is just supposed to go down with no horizontal movement, then it seems that would be a firmware issue.

You may also want to check out the delta 3d robot google group. They are very helpful and can get your issue(s) figured out.

Edited 2 time(s). Last edit at 07/19/2014 12:02PM by Wildcard.

Also your max acceleration rate and max travel rate have different values for the y axis. For the x and z axis you have 1500 for the max acceleration whereas for y axis you have 1200.

Max acceleration you have 3000 for the x and z, and 2700 for the y.


For a delta they need to be the same number on all axises.

This may account for your problem as the y axis would be moving much slower than the others and that would kick the carriage out in a direction.

Still, recheck your firmware settings because it seems like your mechanical dimensions may be off.

Edited 2 time(s). Last edit at 07/19/2014 12:01PM by Wildcard.

Sorry I should have clarified that I am building a Rostock mini. And the different acceleration values were my attempt to fix the problem. It still acts weird if they are all the same.

Also, when moving in z, the x carriage seems to be moving fastest

Did you check your micro-stepping jumpers? If one of them is missing the metal insert or not making contact, it could cause one axis to move faster/slower than the others due to the stepping value being wrong.....

That was it. One of the jumpers on my x axis was only on one pin. You guys are awesome. Thanks a bunch for your help.

No problem! Looking forward to seeing your first print pictures.....